Power unit for machine tools



vJim 0 'C. A. BICKEL EI'AL 2,495,312

POWER UNIT FOR MACHINE TOOLS 1 Filed Jan. 5, 1945 5 Sheets-Sheet 1 ATTORNEY 1950 c. A. BICKEL ET. AL

POWER UNIT FOR MACHINE TOOLS 5 Sheets-Sheet 2 Filed Jan. 5'. 1945 lOb Lug R 1950 c. A. BICKEL ETAL f ,3

POWER UNIT FOR MACHINE TOOLS Filed Jan. 5, 1945 Y 5 Sheets-Sheet 5 J5EE.

INVENTOR CLIFFO and 51cm.

10 smmev afaaanoeua'una H8 BY Tueoooae roman ATTORNEYS 1950 c. A. BlCKEL ETAL 2,495,312

POWER UNIT FOR MACHINE TOOLS 1 Filed Jan 5, 1945 5 Sheets-Sheet 4 L1 lamie i'me ATTORNEY Patented Jan. 24,1950

POWER UNIT FOR MACHINE TOOLS Clifford A. Bickel, Stanley A. Brandenburg, and Theodore Foster, Sidney, Ohio, assignors to The Monarch Machine Tool Company, Sidney, Ohio,

a corporation oi Ohio Application January 5, 1945, Serial No. 571,530

17 Claims.

. 1 This invention relates to power units and, particularly, to geared power units for translating electrical energy into mechanical energy.

In machine tools and the like it is often desired to reciprocate a tool or machine element to and from a working position by means of an electric motor. Also, it is often advantageous to move the movable member rapidly into working position, thereafter to advance it at a reduced rate of speed while accomplishing the work and,

iinally, rapidly to retract it to an idle position.

In lathes and other machine tools the movement of the work tool is usually accomplished by lead screws, feed rods or gear trains driven from the principal power source of the machine. This involves long gear trains and interlocking controls which are expensive to build and assemble and often diflicult to control automatically.

Accordingly it is a principal object of the present invention to provide a unit for reciprocating a work member to and from its working position.

It is another object to provide a unitary device having a built in power unit and control therefor for reciprocating a work tool.

It is another object to provide a device according to the foregoing objects which is adapted to be mounted on the bed or carriage of a lathe or on the column of a drill or other vertical machine tool.

It is another object of the present invention to provide an electrically actuated mechanism for reciprocating a work tool or other machine mem- It is another object to provide an electrically actuated tool reciprocating mechanism wherein the working portion of the advancing stroke thereof is accomplished at reduced speed.

It is another object to provide a device according to the foregoing objects in which the speed of the working portion of the advancing stroke may be varied.

It is still another object to provide a unit, including an electric motor for driving a member, either rotary or reciprocatory, at a plurality of speeds in either direction or to lock the said member against rotation.

It is another object of the invention to provide a unit for accomplishing the foregoing in which the amount of movement of the driven member is precisely controlled.

These and other objects and advantages will become fully apparent upon reference to the following speciflcation taken in connection with the accompanying drawings, in which:

Figure 1 is a diagrammatic view of a lathe 2 a equipped with a tool reciprocating mechanism according to this invention;

Figure 2 is a diagrammatic perspective of the tool reciprocating mechanism;

Figure 3 is a plan section through the tool reciprocating mechanism and is indicated by the line 33 on Figure 1;

' Figures 4, 5, 6, and 7 are sections through the device and are indicated by the lines 44, 5-5, 6-6 and 1-1 on Figure 3;

Figure 8 is a vertical longitudinal section through a portion of the device and is indicated by the line 8-8 on Figure I;

Figure 9 is a side view of the device partly broken away and showing the limit switches and stops which control the reciprocation of the reciprocable portion;

Figures 10 and 11 illustrate one form of electrical circuit adapted to be used in connection with this device; and

Figures 12, 13 and 14 show a modified arrangement of limit switches and stops.

General arrangement This invention, in general, comprises a unit having a stationary bedon which is movably mounted a member such as a work tool support or other machine element. The movable member, which may be a reciprocable carriage or table may be dove-tailed to the bed and is preferably actuated by a nut and screw arrangement.

The screw is adapted to be driven by a motor through a pair of parallel gear trains. Each gear train includes electrically actuated brakes and clutches whereby one or the other or both may be locked against rotation or drlvingly engaged with the said motor.

One of the gear trains also includes a set of change gears so that the rotational speed of the driven screw may be predetermined at will. The other of the gear trains includes a differential unit, the housing of which is drlvingly engaged by the first gear train. The output shaft of the differential drives the table reciprocating screw.

By actuating the clutch associated with one of the gear trains while simultaneously actuating the brake associated with the other of the gear trains the table is reciprocated at a certain speed in one direction. By actuating the other of the clutches and the other of the brakes, the table may be reciprocated in the same direction at reduced speed. By restoring the clutches and brakes to their initial condition, while simultaneously reversing the motor, the table may be reciprocated in the opposite direction at a rapid rate. Also, the table may be caused to dwell at any place by actuating both of the said brakes and, by means of .a time delay device, be caused to dwell for any predetermined period. Thus, very accurate cuts may be made and the workpiece adequately cleaned up at the end of a cut as, for example, against a shoulder or at the bottom of a recess.

The clutches and brakes are preferably electrically actuated and each pair of brakes and clutches are adapted to actuate a single armature which is keyed or splined to the driven shaft.

The direction of forward feed may be reversed at will so that the fast traverse and slow feed stroke may take place in either direction of movement of the table.

The unit is adapted for mounting in any position and may be connected to drive a screw, a shaft, a rack and pinion or any other movable member.

Structural arrangement Referring now to the drawings more in detail and, particularly, to Figures 1 to 9, inclusive, the unit of this invention comprises a main body or bed casting I having a portion I0a attached thereto. Reciprocably mounted upon the bed I0 is the carriage or table I2. The table I2 may be dove-tailed to the bed I0 as indicated at I4 and there may be provided the tapered gib I6 for the purpose of maintaining the dove-tail I4 in precise adjustment.

Mounted on the right end of the unit is a motor I8 which is preferably of an electrically reversible type such as a three phase motor. The shaft 28 of the motor I8 extends into a compartment. 22 formed by the portion "la and the cover plate I0b and within which are a plurality of gears. The shaft 20 has afiixed thereto the pinion 24 which meshes with a gear 26 keyed or otherwise suitably secured to the shaft 28. Also pinned or keyed to the shaft 28, or integral with the gear 26, is a pinion 30 which meshes with an idler gear 32, the latter being journalled on a stub shaft which is fastened to the right side of the wall 38 of the bed portion I011.

The idler gear 32 meshes with a gear 34 which is aflixed to the shaft 36 in any suitable manner. The shafts 28 and 36 are journalled on antifriction hearings in the wall 38. On the opposite side of the wall 38 from the gear 26 the shaft 28 has keyed thereto the portion 40 of a magnetic clutch which also comprises the armature 42. The portion 40 comprises a cored member within which is arranged the coil 44. A sleeve of insulating material 46 is placed on the cored member and the slip rings 48 are mounted thereon. A pair of brushes 50 are mounted on the bed portion I04: and engage the slip rings 48 for the purpose of supplying electrical energy to the coil 44. When the coil 44 is energized the armature 42 is pulled into engagement with the surface of the clutch 40 and a driving engagement between the members 40 and 42 is thereby established.

The shaft 36 has afiixed thereto, on the opposite side of the wall 38 from the gear 34, the clutch 52. The clutch member 52 is constructed similarly to the clutch member 40, having a coil 54 which, when energized, is effective to draw the armature 56 into driving engagement with the clutch member 52.

The armature 42 is splined to a sleeve 58 which is keyed to a shaft 60, the latter being mounted 4 in antifriction bearings in the bed I0. By means of the splined relationship between the armature 42 and the sleeve 58, the armature is free to reciprocate longitudinally of the said sleeve while remaining in driving engagement therewith.

Mounted in the bed I0 on the opposite side of the armature 42 from the clutch member 40 is a cored or hollow member 62 which includes in the hollow portion thereof the coil 64. The coil 64 is adapted, when energized, to draw the armature 42 into engagement with the face of the member 62. The member 62, being fixed in the bed I0, the energization of the coil 64 is effective to hold the armature 42, and, therefore, the shaft 60 against rotation.

Keyed to the shaft 60 is the worm gear 66 which engages the worm wheel 68 (see Figure 5). The worm wheel 68 is keyed to the shaft 10 which extends laterally outwardly from the bed I0 into a compartment I2. The end of the shaft within the compartment I2 is splined as at I4 and carries a similarly splined gear IS.

The gear 16 meshes with a gear I8 which is splined to the shaft which also extends into the compartment I2. The shaft 80 extends inwardly into the bed I0 and has keyed thereto the worm gear 82 which meshes with the worm wheel 84 on the shaft 86. Upon reference to Figures 2 and 4 it will be seen that the shafts I0 and 80 lie in parallel arrangement and that the shaft 86 is in substantial axial alignment with the shaft 60.

The compartment 12 is fitted with a cover 88 which retains the gears I6 and 18 in position. By removing the cover 88 the gears may be removed from the splined ends of the shafts 10 and 80 and other gears having a different ratio inserted in their place.

The shaft 86 extends leftwardly into a compartment 90 at the left end of the bed l0 and has keyed thereto the gear 92. The gear 92 meshes with a gear 94 which is freely journalled on the stub shaft 96, the latter being mounted in the cover 98 of the compartment 90.

Returning to the armature 56, this member is splined through a sleeve to the shaft I00 in a manner substantially identical with the way in which the armature member 42 is splined to the shaft 60. Also fixed in the bed I0 to the left of the armature 56 is a cored brake member 6| similar to the member 62 and including a coil 63. The energization of the coil 63 is effective to draw the armature 56 into engagement with the brake member 6I thereby to lock the shaft I00 against rotation.

The shaft I00 extends into the right end of a difierential unit I02 and has keyed thereto the bevel gear I04. Meshing with the gear I04 are the bevel gears I06 which are freely journalled on the shaft I08 which extends transversely of the housing IIO of the differential I02.

Also in mesh with the gears I06 is the gear II2 which is attached to the shaft H4. The shaft II4 extends out the left end of the differential and into the compartment 90 where it has affixed thereto the gear H6.

The gear H6 is in mesh with the gear II8 which is freely journalled on the stub shaft 96 and is also in continuous mesh with the pinion carried by the screw I22.

The screw I22 is supported in suitable antifriction bearings such as the thrust bearings indicated at I24 (Figure 8) and is in threaded engagement with the nut I26 which is attached to the table or carriage I2.

Returning to the differential unit I02, the

housing I I thereof is rotatably journalled within the antifriction bearings I28 in the bed I0, and has afllxed to the left end thereof, within the compartment 90, the gear I80. The gear I30 is continuously in mesh with the gear 84 which, as previously mentioned, is freely journalled on the shaft 96.

Referring to Figures 6, '7 and 9, it will be seen that the table I2 comprises a T slot I32 on one side thereof which is adapted to receive a plurality of cam members indicated at I34, I36 and I38. The cam members are adapted to actuate the limit switches I40, I42 and I44 (Figure 9) which are mounted within the compartment I46 of the bed I0. The switch I has associated therewith the spring loaded plunger I41 which is adapted to be engaged by the cam member I34 when the table I2 is in its extreme right hand position. Similarly associated with the switch I44 is the spring loaded plunger I48 which is adapted to be engaged by the cam I38 when the table is in its extreme left hand position. The cam I36 carries an arm I50 which is adapted to engage a spring loaded plunger I52 associated with the switch I42 as the table I2 moves leftwardly thereby to actuate the said switch. As the table I2 moves rightwardly the arm I50 pivots about the pin I54 and thus passes over the plunger I52 without actuating the switch I42. Suitable means such as the spring pressed plunger I56 ma be provided for urging the arm I50 into its Figure 9 position after it has passed over the plunger I52 during the leftward movement of the table I2.

Electrical circuit In Figures 10 and 11 is shown the electrical circuit which controls the actuation of the clutches and brakes and of the motor.

The motor I8 is preferably a three phase motor but may be of any other type which may be electrically reversed by means of relays. The relays and contactors are supplied with direct current power from any suitable source such as a generator or electronic rectifier.

Referring to Figure 10 the direct current power supply lines are indicated at LI and L2. Connected between the lines LI and L2 is a contactor coil A which is adapted to be energized by the closing of the switch I58. Associated with the contactor coil A are the normally open blades AI and A2 which, upon being closed by the energization of the contactor coil A, conduct power to the motor I8 from the three phase power lines L3, L4 and L5, (Figure 11) Connected between LI and L2 is the contactor coil B which has in series therewith the normally open push button I60 and the normally closed contactor blades CI. The contactor coil B is operable, when energized, to close the contactor blades BI and B2, and to open the blades B3. The blades CI and the switch I60 are bypassed by a line including the normally open blades BI, the normally closed contacts of push button switch I62, the normally closed contacts of the single pole double throw limit switch I42, the normally closed contacts of the single pole double throw limit switch I44, the normally closed contacts of the push button switch I88, and the normally closed contacts of limit switch I40. The push button switch I50 and the normally closed blades CI are further bypassed by a line I64 which includes the normally closed blades EI, the normally open blades F2 and FI, line I18,

the normally closed contacts of push button switch I80, and the normally closed contacts'oi.

limit switch I40.

The contactor coils C and D are connected between the lines LI and L2 by a line which includes the normally open contact blades DI of the contactor coil D, the normally closed contacts of single pole double throw limit switch I44, the normally closed contacts of push button switch I68, and the normally closed contacts of limit switch I40. Also connected serially with the contactor coil C is the push button switch I12 having the normally closed contacts I12a andthe normally open contacts I121). The contactor coil C is operable, when energized, to close the blades C2 and C3 while opening the blades Cl, C4 and C5. The contactor coil D, when energized, closes the blades DI.

A contactor coil E, having normally closed blades'EI, is connected between the lines LI and L2 through the normally open contactor blades C2 of the contactor coil C. Connected in parallel with the contactor coil E is a condenser I14 which has shunted there across the adjustable resistor I16. Serially connected with the resistor I16 are the normally closed blades C5 of thecontactor coil C. The condenser resistor arrangement is for the purpose of delaying the opening of the contactor coil E for a purpose which will be described hereinafter.

A pair of contactor coils F and G are connected between the lines LI and L2 through a pair of normally open contactor blades Fl, the normally closed contacts of the push button switch I68 and the normally closed contacts of limit switch I40. Contactor coil B is shunted with contactor coils F and G through the normally open blades F2 and normally closed blades E I.

The coil 54 of the clutch member 52 is connected between the power lines through the normally open blades B2 of the contactor B while the coil 63 of the brake member Si is connected between the power lines through the normally closed blades B3 of the contactor B.

The coil 44 of the clutch member 40 and the coil 64 of the brake member 62 are connected between the lines LI and L2 by the normally open contacts C3 and the normally closed contacts C4 respectively.

The contactor coil G is for the purpose of reversing the direction of rotation of the motor I8 and, to this end, has associated therewith the contact blades GI, G2, G3 and G4 (Figure 11). The blades GI and G4 are normally closed and in series with the blades AI and A2 of the contactor coil A. When the contactor coil G is energized, the blades GI and G4 open while the blades G2 and G3 close thus reversing the phase rotation of the motor I8, and, therefore, also the direction of rotation thereof.

Operation Assume that the device of this invention is mounted on the bed of a lathe as indicated in Figure 1 wherein the lathe may comprise a bed I80, a headstock I82 and a Work holding means at I84 which supports a workpiece I86.

Any suitable and well known system of controls may be used in association with the lathe. By way of example a tool holder I88 is mounted in the T slot I90 of the table I2. Supported in the tool holder I88 is a drill I92. The drill is adapted, upon actuation of the bed I2, to engage the workpiece I86 and to perform a working operation thereon.

'glzes the motor I8 to run in a forward direction.

The operator then closes the push button switch III to energize the contactor coil B, a holding circuit for which is established through contact blades BI push button switch I82, limit switch I42, limit switch I44, push button switch Ill and limit switch I40.

Energization of the coil B is eflective to close the blades B2 while opening the blades B8 in.

addition to the closing of the aforementioned blades BI. The closing of the blades B2 energizes the coil 64 of the clutch member 52 while the opening of the blades B3 deenergizes the,

brake coil 83 of the member 8I The armature '56 is thus moved rightwardly into driving engagement with the clutch member 62. At the same time the. coil 84 of the brake member 62 is energized while the coil 44 of the clutch member 40 is deenergized, thus moving the armature 42 into engagement with the said brake member.

The mechanical drive from the motor to the screw I22 is now through the shaft 20 into the gear 24, thence into the gear 28 and through'the shaft 20 into the gear 30. From the gear 30 power is transmitted through the idler gear 82 into the gear 34 and thence through the shaft 86 into the clutch member 52 and the armature 56.

Rotation of the armature 58 drives the shaft I and the gear I04 of the differential unit I82.

As mentioned before, the armature 42 is locked against rotation by the engagement thereof with the brake member 62. The shaft 60 is thus held against rotation and the gear train in-' eluding the worm gear 66, worm wheel 88, the

gears I6 and I8, the worm gear 82, the work wheel 84 the gears 92 and 84 is held against rotation. The engagement of the gear 84 with the gear I80 keyed to the housing IIO of the differential unit I02 is effective to hold the said differential housing against rotation. Accordingly, the aforementioned rotation of the bevel gear I04 is effective through the gears I06 to rotate the gear H2.

The rotation of the gear H2 is transmitted through the shaft I4 to the gear I I6 which, in turn, drives the gear H8. The gear II8 drives into the gear I on the screw I22 and the said,

screw is thereby rotated. Rotation of the screw I22 moves the table I2 leftwardly until the cam I38 engages the plunger I52 of the limit switch I42. The cam member I38 is preferably adjusted so that the arm I50 thereof actuates the plunger I62 slightly before the tool I92 engages the workpiece I86.

When the limit switch I 42 is actuated, the holding circuit to the contactor coil B is broken, thereby deenergizing the same. permits the blades B2 to open and the blades B2 to close, thereby deenergizing the clutch coil 54 while simultaneously energizing thebrake coil 83. The actuation of the switch I42 also completes a circuit to the contactor coils C and D which are held by the circuit established through the contactor blades DI, the limit switch I44, the push button switch I88, and the limit switch I40. Energization of the contactor coll C opens the blades CI and C4, while simultaneously closing blades C2 and C3. The closing of the blades C3 energizes the clutch coil 44 of the clutch member 40, while opening of the blades C4 de- Deenergizing of B.

energizes the brake 'coil 84 of the brake member 82.

Thus, the armature 42 is held in driving engagement with the clutch member 40 while the armature56 is moved into engagement with the brake member associated therewith.

The drive from the motor I8 is now through the shaft 20, the gear 24 and the gear 28 into the shaft 28. The shaft 28 drives the clutch member 40 and the armature 42.

.The rotation of the armature 42 rotates the shaft and the worm gear .88. The worm gear 88 drives through the worm wheel 68 into the shaft 10 and thence through the gears 16 and I8 into the shaft 80 and the worm gear 82. The worm gear 82 drives into the gear 84 and the shaft 88 into the gear 92. The gear 82 drives the gear 94 which is in mesh with the gear I20 of the differential unit I02.

As mentioned before, the armature 58 is locked against the brake member 8| and the shaft Ill and the gear I04 are thereby held against rotation. Thus, as the gear 94 rotates the gear I20 and the housing IIO of the difierential unit I02, the shaft I I4 is rotated by the cooperation of the gears I08 with the stationary gear I04 and the gear II2 on the said shaft.

As before, rotation of the shaft I I4 rotates the gear I I8 which drives the gear I I8 which in turn drives the screw I22 through the pinion I20. The direction of rotation of the screw I22 is such that the table l2 continues to move in the same direction but the gear ratio between the motor I8 and the said screw is such that the said table moves at a reduced rate. The change gears 16 and I8 determine the particular rate of movement of the table I2 and are selected so that the said rate has, an optimum value.

The table I2 continues to move left at reduced speed, until the cam I38 engages the plunger I48 of the switch I44 and interrupts the holding circuit to the contactor coils C and D. Deenergization of the contactor coil C permits the blades C2 and C3 to open, while the blades CI, C4 and C5 close.

The opening of the blades C2 deenergizes the coil 44 of the clutch member 48 while the closing of the blades C4 energizes the coil 84 of the brake member 82. This again moves the armature 42 into engagement with the brake 62 thus holding the former against rotation.

The actuation of limit switch I44 also completes a circuit to contactor coils F and G, and the motor I8 is reversed by the opening of blades GI and G4, and the closing of blades G2 and G8. As contactor coil F is energized, blades FI and F2 are closed. Blades FI complete a holding circuit for the coils of contactors F and G. Blades F2 complete a holding circuit for the coil of contactor B. The closing of blades F2, however, is not effective to energize the coil of contactor B until blades EI have closed. The contactor coil E remains energized for a predetermined length of time, while the energy stored therein is dissipated through the condenser resistor arrangement I14, I18. The resistor, being adjustable, may be set to predetermine this time interval within relatively close limits.

It will be noted that, at this time, both of the brake coils are energized so that the entire gear train to the table reciprocating screw I22 is locked. The table I2 is thus locked in position and dwells for a, predetermined length of time determined by the aforementioned time delay circuit.

Upon the accomplishment of the time delay period, the contactor E drops out and closes the blades EI' associated therewith. The closing of blades El establishes a circuit from the line L2 through the contactor coil Bthrough blades F2, blades Fl, push button switch I68 and limit switch I40 to line LI. The contactor coil B is thereby energized, and the blades B2 are closed to energize the coil 54 of the clutch member 52, while the blades B3 open and deenergize the the brake coil 63 of the brake member GI.

The clutches and brakes are now energized in the same manner as they were when the table I2 was moving rapidly to the work. However, the motor I8 is revolving in the opposite direction and the screw I22 is also revolving in the opposite direction. Therefore, the table I2 is retracted from the work at a relatively high rate of speed.

During the retraction stroke of the table I2,

. the cam I136 passes over the plunger I52 but does not actuate it because of the pivoted arm I50.

The table I2 continues its retraction stroke until the cam member I34 engages the plunger MT andactuates the limit switch I40.

The actuation of the limit switch I40 interrupts the holding circuit for the contactor coil B so that the blades B2 open and deenergize the coil 54 while the blades B3 close and energize the coil 83.

The actuation of the switch I40 is also effective to interrupt the holding circuit of the contactors F and G thereby deenergizing the said contaotors. The deenergization of the contactor coil G permits the blades GI and G4 thereof to close while the blades G2 and G3 are opened. This restores the original electrical connections to the motor M3 for rotation in a forward direction.

III

drawings, but is capable of being modified in various manners. For example, the lathe illustrated in Figure 1 could additionally comprise a unit mounted to reciprocate a tool transversely of the axis of the workpiece without in any way departing from the spirit of this invention. Likewise, the device of this invention could be mounted vertically so as to present a tool to the upper surfac of the workpiece, if desired.

The differential unit at I02, while it is, illustrated as a geared device employing bevel gears, could, it will be understood be replaced by a planetary or epicyclic gear train if found desirable. Likewise, although the output member is shown as a screw, it will be apparent that a rack and pinion or a drive shaft many other power absorbing or transmitting means could be actuated by the output shaft H4.

It will also be apparent that while only one drive motor is shown in the drawings there could be a drive motor for each of the shafts 28 and 38 and that these motors could be reversible and variable speed or constant speed as desired.

It will be noted that both of the brake coils 6t and 64 are again energized so that the table i2 is once more locked in position.

The device is now ready for a new working cycle which may be instituted by depressing a button N50.

The push button switch I12 is provided for the purpose of halting the feeding of the tool into the work whenever desired, and also for the purpose of inching the table I2 forward.

The push button switch I00 may be depressed at any time to return the table I2 to its initial position, while the push button switch I62 may be depressed at any time during the rapid traverse of the table I2 toward or from the work to stop the movement of th said table or to inch" the same.

Modified construction of Figures 12, 13 and 14 Referring now to Figures 12, 13 and 14, a modi-' fled arrangement for actuating the control limit switches is shown.

The table I2 has attached thereto a tail piece on which is mounted a switch I08.

The table reciprocating screw I22 has a rearward extension I98 which carries a drum.

The drum 200 has spirally arranged therearound a plurality of holes 202 which are adapted to receive the buttons 204 which are adapted to actuate the plunger of the limit switch I96.

By calibrating the drum, the buttons 204 may be placed therein so that any predetermined travel of the table l2 may be obtained. This travel may be divided into rapid forward traverse and slow forward traverse as desired.

It will be apparent that this invention is by no means limited to the specific structure and arrangement and application illustrated in the These motors could also comprise braking means integral therewith in which case the brake units GI and 62 would b eliminated and the shaft 60 and I00 made integral with the shafts 20 and 36, respectively.

In the event that exceedingly close control of the driven member was not required, the motors could drive through self-locking worm gears into the shafts 28 and 36 and, if suitable controls were provided, the motors could be energized to actuate the shafts and de-energized to lock them. Thus, while it is preferable, for the accurate control of the driven member, to employ electrically actuated clutches and brakes for driving and for braking the shafts 60 and I00, in certain instances other, less precise, electrically actuated means could be provided for performing this function.

Accordingly, it is desired to comprehend such modifications in arrangement and structure and substitution of equivalents as may be considered to come within the spirit of the invention and the scope of the appended claims.

We claim:

In combination with a source of power and a member to be driven, a first means for driving said member from said source of power, a second means for driving said member from said source of power, electrical means for selectively rendering said driving means effective or ineffective and a control circuit for controlling said electrical means and adapted automatically in response to predetermined movements of said driven member for bringing about the actuation of said electrical means, said first means including a variable speed transmission connected between said source of power and said driven member for adjusting' the speed of the latter.

2. In a power transmission, a member to be rendering effective said first means thereby to cause said source of power to move said member at a second predetermined speed, said first means including a variable speed transmission connected between said source of power and said driven member for adjusting the speed of the latter.

3. A power transmission adapted for interconnecting a reversible source of power with a driven member comprising an output member adapted to be drivingly connected with saiddriven member, a first interconnecting means connecting said output member with said source of power, and a second interconnecting means connecting said output member with said source of power, said second means including a geared differential having its input shaft driven from said source of power and its output shaft in driving engagement with said output member, said first means including a variable speed transmission connected between said source of power and said driven member for adjusting the speed of the latter.

4. A power transmission comprising a source of power, an output member, a first and a second interconnecting means connecting said source of power with said output member, said second means including a geared differential having its output shaft in driving engagement with said output member and its housing in driving engagement with said first means, and electrical control means automatically operable to disconnect either said first or said second means from said source of power, said first means including a variable speed transmission connected between said source of power and the housing of said differential for adjusting the speed of the latter.

5. A power transmission comprising a reversible motor, an output shaft adapted to be driven in both directions by said motor, a first and a second interconnecting means connecting said motor with said shaft, each of said means including clutch means operable in response to the movement of said output shaft to connect or disconnect said means from said motor, said first means also including a variable speed transmission comprising change gear means connected between said motor and said output shaft.

6. In a power transmission a source of power, a movable member adapted to be driven by said source of power, first shaft means interconnecting said source of power with said movable member, second shaft means connected with said source of power and including a gear differential, means drivingly connecting said first shaft means with the housing of said differential unit, electrically actuated cluch means associated with each of said shaft means operable to disconnect the same from said source of power, electrically actuated brake means associated with each of said shaft means operable to lock the same against rotation, and a common control circuit adapted automatically in response to the movements of said member for controlling the energization of said clutch and brake means.

7. In a power transmission a source of power, a movable member adapted to be driven by said source of power, first shaft means interconnecting said source of power with said movable member, second shaft means connected with said source of power and including a geared differential, means drivingly connecting said first shaft means with the housing of said differential unit, and electrical control means including clutch and brake means for each of said shaft means and being operable to disconnect either or both f 12 said shaft means from said source of power while simultaneously locking the same against rotation.

8. The combination in a power transmission of a geared differential having an output shaft, an input shaft and a rotatable frame, driving means for driving said input shaft and said frame, clutch means operable to connect or to disconnect said input shaft and said frame from said driving means, brake means operable to lock either said input shaft or said frame or both against rotation, common control means operable in response to the movement of said output shaft for controlling the actuation of said clutch means and said brake means, and a variable speed transmission comprising change gear means connected between said driving means and said rotatable frame.

9. The combination in a power transmission of a geared differential having an output shaft, an input shaft and a rotatable frame, a motor for driving said input shaft at a substantially con stant speed, clutch means operable to connect said input shaft to said motor, brake means operable to lock said input shaft against rotation, means including gear change means for driving said differential frame at selectable speeds from said motor, clutch means for connecting said frame with said motor, brake means for locking said frame against rotation, and control means for controlling the actuation of said clutches and said brakes in response to the movements of said output shaft.

10. The combination in a power transmission of geared differential means having an output shaft, an input shaft and a rotatable frame, driving means for driving said input shaft and said frame, electrically actuated clutch means operable to connect said input shaft with said driving means or said frame with said driving means, electrically actuated brake means operable to lock said input shaft or said frame or both against rotation, electrical control means for controlling the actuation of said clutch means and said brake means, and a variable speed transmission comprising change gears located between said driving means and said differential means.

11. In a power transmission, a geared differential having an output shaft, an input shaft and a frame, means rotatably supporting said frame, a single driving means for driving said input shaft and said frame, magnetic clutch and brake means operable to connect said driving means with said input shaft while holding said frame against rotation, or for connecting said driving means with said frame while holding said input shaft against rotation, said magnetic means also being operable to hold both said input shaft and said frame against rotation, and a variable speed transmission connected with said driving means and said frame for adjusting the speed of the latter.

12.- In a power transmission, a geared differential having an output shaft, an input shaft and a frame, means rotatably supporting said frame, a motor adapted to drive said input shaft or said frame, gear change means for adjusting the speed at which said frame is driven, magnetic clutch means operable to connect either said frame or said input shaft with said motor while simultaneously locking the other against rotation, means for locking both said frame and said input shaft against rotation, and control means automatically operable for controlling the a frame, means rotatably supporting said frame,

a reversible driving means for driving said input shaft or said frame, means including change gears for adjusting the speed at which one of said frame and input shaft is driven, clutch means operable to connect said input shaft on said frame with said driving means, brake means operable to lock said input shaft against rotation when said frame is being driven or viceversa, said brake means also being operable to lock both said frame and said input shaft against rotation simultaneously, and control means operable to control the actuation of said clutch means and said brake means and the direction of rotation of said driving means whereby said output shaft may be operated ata first or a second speed in one direction or operated in the other direction. 14. In combination with a member to be reciprocated, a geared differential having an-output shaft in operative association with said reciprocable member, said differential also having an input shaft and a rotatable frame, a motor for driving said input shaft or said frame, means operable to disconnect either said input shaft or said frame or both from said motor, and control means operable in response to a predetermined reciprocation of said reclprocable member for controlling the actuation of said disconnecting means. 15. In combination with a reciprocable member, a geared differential having an output shaft, an input shaft and a frame, means rotatably supporting said frame, means including a screw and nut drivingly interconnecting said member with said output shaft, a motor for driving either said input shaft or said frame, means for holding said frame against rotation while driving said input shaft from said motor in a first direction in order to effect a rapid advancing movement of said reciprocable member, means operable in response to a predetermined advancing movement of said member for driving said frame from said motor while holding said input shaft against rotation for effecting further advancing movement of said reciprocable member at reduced speed, means operable in response to a predetermined further advancing movement of said member for holding said frame against rotation while driving said input shaft from said motor in a second direction for effecting the retracting movement of said reciprocable member, and means operable in response to a predetermined retracting movement of said member for holding both said frame and said input shaft against rotation.

16. In combination with a reclprocable member, a differential unit having an output shaft, an input shaft and a frame, means rotatably supporting said frame, means including a screw and nut drivingly interconnecting said member and said output shaft, a motor for driving either said input shaft or said frame, means for holding said frame against rotation while driving said input shaft from said motor in a first direction in order to effect a rapid advancing .movement of said reciprocable member, means automatically operable in response to a predetermined advancing movement of said member for driving said frame from said motor while holding said input shaft against rotation for eflecting fur- ,ther advancing movement of said reclprocable ,member at reduced speed, means automatically ,-0perab1e in-response to a predetermined further advancing movement of said member for holding both said frame and said input shaft against rotation for a predetermined period of time,

means automatically operable at the end of said predetermined period for holding said frame .against rotation while driving said input shaft response to a predetermined retracting movement of said member for holding both said frame and said input shaft against rotation. I

1'1. In combination with a member to be reciprocated, a bed upon which said member is 'reciprocable, a geared differential having its output shaft connected with said member, said differential also having a frame joumalled in said bed and an input shaft, a motor for driving either said input shaft or said frame, a first electrical means operable to hold said frame against rotation while driving said input shaft from said motor in one direction to effect the initial advancing movement of said reciprocable member, second electrical means automatically operable in response to a predetermined advancing move"- ment of said member for holding said input shaft against rotation while driving said frame from said motor to effect further advancing movement of said member, third electrical means automatically operable in response to a predetermined further advancing movement of said member for holding both said frame and said input shaft against rotation, and electrical timer means automatically operable in response to the expiration of a predetermined period for continuing to hold said frame against rotation while 'driving said input shaft from said motor in the reverse direction for effecting the retracting movement of said reciprocable member.

CLIFFORD A. BICKEL. STANLEY A. BRANDENBURG. THEODORE FOSTER.

file of this patent:

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